In the following Patent Document 1, a solenoid valve composed of a main valve portion having a valve member for switching a flow path and a solenoid operation portion for operating the valve member is disclosed. In the solenoid valve, the solenoid operation portion contains, inside a U-shaped magnetic frame, a hollow bobbin having an exciting coil wound therearound; a magnetic plate disposed on one end side in the axial direction of the bobbin and magnetically coupled to the magnetic frame; a fixed iron core fixedly set inside the inner hole of the bobbin and magnetically coupled to the magnetic frame; a movable iron core movably provided inside the inner hole of the bobbin and the magnetic plate, and attracted to the fixed iron core by magnetic attraction generated by the flow of electric current through the exciting coil; and an iron core return spring for making the movable iron core return to the initial position separated from the fixed iron core. Then, the valve member is driven by the movable iron core.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-156709
However, in such a solenoid valve, although the movable iron core moves inside the inner holes of the bobbin and the magnetic plate, at that time, when the movable iron core slides in contact with the magnetic plate, the resistance caused by sliding between metals increases and there is a fear that the movable iron core loses smooth movement. Furthermore, a problem in that damage such as scratches and wear are caused on the surface of the movable iron core and the magnetic plate by sliding between metals easily occurs.